Adjusting a Blown forge

[Daniel Rohde]

Hey guys!
My question is this. say your running your forge at 1800F for forging and you want to go to forge welding temp how can you adjust the air and gas correctly to get the right gas/air mix? basically how do you tune your burner while it's running? and what are the right mixtures for general forging...and forge welding.
Thanks!
Daniel

 

[CWendling]

Not to be a smart alec, but add gas and air. You will have to learn what works for your forge. Every forge will run differently as to how much has to be added to raise the temperature and to keep a reducing atmosphere because of different shapes and sizes of the forges etc.

 

[Salem Straub]

I usually add a bit of gas, observe the flame lengthen coming out the door, then add air until the amount of flame coming out the door is what I want for what I'm doing. To run lower, I cut either the air or gas back and then cut the other back until the flame looks how I want.
When the forge is cold, it will run a bit different than when it's been running for a few minutes- often the gas will need to be cut back a little or more air added. Then, 20 min. into a forge welding session, I find my vertical forge can be run lower and more fuel-rich, which helps your welding and saves gas.
To paraphrase Cory, you will ultimately get to know your forge very well- they are all different.

 

[Stacy E. Apelt - Bladesmith]

Salem has the right sequence. You want to always adjust with the atmosphere becoming rich first, and then change the mix to get a clean dragon's breath. The desired flame coming out the forge is :
1) as small as possible/needed
2) Not yellow
3) not screeching or making strange sounds
4) a neutral blue color to invisible.

To raise the temp, add gas first and then add air. To lower reduce the air and then reduce the gas. Listen to the forge as it adjusts and runs. A warmed up forge can almost be tuned by ear.